Park Highlights

Canaveral

National Seashore

Florida

Canaveral National Seashore, Florida

PHYSIOGRAPHY

The entire state of Florida is located on the Floridian Plateau (Fernald and Patton 1984). The plateau is approximately 500 miles in length and between 250-400 miles in width (Fernald and Patton 1984). The plateau includes both emergent land and submerged continental shelf. This plateau has existed for millions of years and has been alternately covered by seawater and exposed as dry land many times. This has created areas where marine and terrestrial deposits have been deposited one on top of the other.

The barrier island complex, including the Mosquito Lagoon sub-basin, has taken an estimated 240,000 years to form and is the result of multiple rises and falls in sea level (Fernald and Patton 1984). More specifically, the east coast of Florida is formed mainly by eroded relict dune lines and broad marine terraces, as well as the present barrier islands and lagoon system. Terraces were formed during the high stillstands, which allowed erosion by waves and currents to form flat plains that emerged as flatlands when the sea level subsided (Brooks 1982; Glatzel 1986). The lowest terrace in the Mosquito Lagoon watershed is called the Silver Bluff Terrace. As the sea level receded, dune ridges, including the Atlantic Coastal Ridge, formed on this terrace (Schnable and Goodell 1968). The Mosquito Lagoon drainage basin is bordered by the Atlantic Coastal Ridge on the west and the Atlantic Beach Ridge (Barrier Islands) on the east.

The physical features presented here represent a compilation of existing information concerning the physical characteristics of the Mosquito Lagoon sub-basin. An understanding of these features is critical since they determine the ecosystem. In particular, the physical features determine biological habitats, define the sources and transport of pollutants, and outline human usage. For over a century, many large and small projects have been carried out throughout the IRL to aid navigation, drain floodwaters, control mosquitoes, provide access to the barrier islands and stabilize tidal inlets. These projects have substantially changed many of the physical features of the Lagoon, including infiltration, runoff, shallow-aquifer storage and land drainage capacities. In some cases, such as the mosquito impoundments, where the natural functions of the IRL have been degraded, efforts are presently underway to return the habitat to its natural state.

Mosquito Lagoon was created by a small number of physiographic features. A predominant physiographic land feature of the barrier island system in this area is Cape Canaveral. Cape Canaveral was described by Stauble (1988) as a .cuspate foreland. similar to Cape Hatteras in North Carolina, in which a sandy cape has developed where offshore currents meet. The Mosquito Lagoon barrier islands were created, in part, by this .cuspate foreland. of Cape Canaveral (Stauble 1988). Additionally, to the north, the flood tide delta of the migrating (until stabilized) Ponce de Leon Inlet and a now-closed second inlet that was located near Bethune Beach influenced the physiography of Mosquito Lagoon (Stauble 1988). Unlike many barrier islands, the barrier islands associated with Mosquito Lagoon have only a single dune ridge averaging 12 feet in height (Woodward-Clyde 1994b). For the vast majority of its length, the dune is quite stable, backed by a dense growth of saw palmetto (Serenoa repens) and several other species of hardy shrubs and grasses (National Park Service 1997).

In the past, many inlets have been formed across the Mosquito Lagoon barrier island system, but have since naturally closed. The most recent of these inlets was located near Turtle Mound and closed around 500 AD (Mehta and Brooks 1973). Vegetated flood-tidal (lagoon side) deltas and oyster beds in the geological strata are remnants of these historic inlets, suggesting that these areas were once open to tidal flushing (Mehta and Brooks 1973; Woodward-Clyde 1994b). The only present-day connection of Mosquito Lagoon to the Atlantic Ocean is through Ponce de Leon Inlet (Figure 1). This naturally migrating inlet marks the northern end of both Mosquito Lagoon and the Indian River Lagoon system. Because of the dynamic behavior of the shoreline on both sides of the inlet and the shoaling of its mouth, a stabilization project by means of jetties was conducted between 1968 and 1972 (Woodward- Clyde 1994b). Presently, the direction of longshore currents and associated erosion and deposition associated with the stabilized Ponce de Leon Inlet is not well understood and differs between models (e.g. Stauble and DeCosta 1987; Taylor et al. 1991).

Some areas along the barrier island of Mosquito Lagoon are very narrow, which makes them susceptible to over-wash and likely spots for inlet formation. In the fall of 1999, small, .temporary inlets. were formed from over-wash at several spots along the barrier island during storms associated with the hurricane season. These overwashes may become larger and more frequent if hurricane intensity and frequency increase. Also, if global warming continues as
predicted, sea level rises will acerbate these impacts.

The only direct hydraulic link between Mosquito Lagoon and the Indian River proper is through Haulover Canal, a man-made canal constructed to replace an overland system of transporting boats (Figure 1). The original Haulover Canal was excavated in 1854 but is no longer in use (Hutchinson 1987). In 1887, a larger canal was built approximately one-half mile to the north through the Cape Canaveral Complex Ridge and is still used today. In the past, Mosquito Lagoon may have been connected to the rest of the IRL system to the south by channels north and west of Cape Canaveral (Mehta and Brooks 1973; Almasi 1983).

ESTUARINE SETTING

The Indian River Lagoon (IRL) System stretches 156 miles from Ponce de Leon Inlet at the northern end to Jupiter Inlet at the southern end and covers a full 40% of Florida.s east coast (Figure 1). Despite its name, the Indian River Lagoon is not a river. It is an estuary . a water body in which the mixing of fresh and salt water occurs. Ocean water enters the IRL system through inlets, while freshwater enters the Lagoon through rainfall, groundwater seepage, and as discharge from streams, creeks, rivers and canals. The salinity profile of a particular segment of
the Lagoon depends on its proximity to inlets and freshwater inputs and the specific physical and geographic features of the area.

Estuarine communities cover much of the Atlantic and Gulf coasts of the United States and are characterized by both high productivity and high biodiversity (Provancha et al. 1992). In fact, estuaries are among the most productive ecosystems on earth (Bertness 1999). High primary productivity of estuaries reflects their nutrient-rich conditions and the presence of many primary producers, including micro- and macroalgae, seagrasses and emergent grasses, scrub, and trees. These primary producers in turn provide important spawning and nursery habitat for many species of fish and invertebrates. Approximately 72% of commercial and 74% of sport species of fish and invertebrates must spend all or part of their lives in or associated with an estuarine system (Durako et al. 1988).

Estuaries serve as buffers between the oceans and the land, providing an important ameliorating zone for storms and floods. For example, a fringe of salt marsh only 8 feet wide can reduce wave energy by over 50%. Estuaries also serve as important sinks for materials (nutrients and contaminants) that flow from the land, catching pollutants before they reach the ocean (Durako et al. 1988). Additionally, estuaries can be very important to the recreational and tourism industries and serve as important transportation routes (i.e. ICW).

Three distinct bodies of water make up the IRL system: the Indian River, the Banana River and Mosquito Lagoon. Mosquito Lagoon is the northernmost sub-basin of the IRL system and is a bar-built type estuary occupying 152.8 km2 (Clapp 1987). Canaveral National Seashore is responsible for maintaining and protecting a large portion of Mosquito Lagoon. Unfortunately, as the background information in this Water Resources Management Plan will point out, many
aspects of the biology and geology of Mosquito Lagoon have not yet been adequately addressed. Issues deemed most critical by scientists and CANA Resource Managers will be addressed in the final section of this report as project statements.

SOILS

The soils comprising the Indian River Lagoon watershed are characterized by location-specific geologic, hydrologic and biological factors. Soil surveys of this region are currently being conducted by the State of Florida. Overall, in the Mosquito Lagoon region, four types of landforms and associated soils can be found (Woodward-Clyde 1994b). Barrier island sands are sandy throughout, frequently contain shell fragments, and are classified as either well drained or
excessively drained (Figure 10). Well-drained soils are defined as soils that are very permeable and have high infiltration rates. Excessively drained soils have a wet season water table greater than six feet deep and are generally permeable. Soils from the mainland coastal ridge vary from excessively drained to poorly drained. Some mainland coastal ridge soils have weakly cemented, sandy subsoil that is underlain by loam. Soils of the flatwoods are very level and
poorly drained. Most have a sub-soil that is sandy in the upper layers and loamy in the lower portions. Flatwood sub-soils also frequently contain organic matter or iron. Finally, tidal marsh soils are nearly level and range from poorly to very poorly drained. Some tidal marsh soils are organic throughout, while others have stratified layers of sand and clay. Soil types are very important due to the presence of septic tanks along the edge of Mosquito Lagoon.

SEDIMENTS

The sediments in the Indian River Lagoon are dynamic and the settling basin is constantly changing in shape and composition (Woodward-Clyde 1994a, 1994c). Sediment build-up in the Lagoon has been identified as a physical problem. Deposition and erosion interfere with navigation and can change the tidal regime within the estuary. Additionally, many aquatic organisms that have low tolerances for sediment accumulations, such as the eastern oyster Crassostrea virginica, are potentially being smothered by high loadings (Walters et al. 2001). It is imperative that we better understand the movements and sources of the sediment flux in the waters of CANA.

The bottom of Mosquito Lagoon contains sandy sediments, comprised mostly of quartz and shell fragments (Woodward-Clyde 1994a). The sand and shell particles that comprise these sandy sediments have relatively low affinities for particle-reactive contaminants in comparison to more fine-grained sediments (Woodward-Clyde 1994a). Another type of sediment that can be found in the Lagoon is fine-grained, organic-rich mud commonly referred to as .muck. (Woodward-Clyde 1994a). Muck is more frequently associated with particle-reactive contaminants, including synthetic organic compounds and metals.

Muck deposits cover very little of the bottom of Mosquito Lagoon and are usually found in relatively deep or sheltered areas where wave action and current strength are limited, such as the ICW. The last IRL system-wide sediment survey found no major muck deposits between New Smyrna and Oak Hill (Trefry et al. 1990). South of Oak Hill, three minor muck deposits were found in the ICW. It is believed that the deposits may be a result of the transport of soil and organic material from the more developed northern and central regions. Where present, muck deposits can vary in thickness from less than 0.5 inch (1 cm) to greater than 6 feet (1.8 m), as has been found in central regions of the IRL system (Trefry et al. 1990).

The SJRWMD SWIM Plan is suggesting a resurvey within the next 5 years given that TSS and TN concentrations in the southern portion of Mosquito Lagoon have dramatically increased in the last few years. If the sediment survey should reveal an appreciable expansion of muck deposits, a proposal to accelerate the ICW dredging schedule can be submitted to the ACOE. Lagoon-wide investigations in sediment particle re-suspension and optical properties of suspended material may provide major clues as to what type of suspended material most
influences turbidity and light penetration. A study of the composition of the sediments would also be important for identifying and controlling specific sources of TSS and TN.

HYDROGEOLOGY

The state of Florida has more available ground water than any other state within the United States (McGuinness 1963). Potable ground water can be found throughout most of Florida, with the exception of a few areas near the coast (Conover et al. 1984). In 1980, 51% of the total fresh water used in Florida was ground water. There are three basic units of the hydrogeologic framework underlying Florida and the Indian River Lagoon system: the Floridan Aquifer, the
intermediate aquifer (regional confining unit) and the surficial aquifer (Figures 16 - 18; Appendix C).

The Floridian Aquifer is a system of limestone and dolomite beds, and is the main source of potable water in Volusia County (Phelps 1990). The raw water supply for the Utilities Commission of New Smyrna Beach (UCNSB) is derived from 19 deep wells obtaining groundwater from the Floridan Aquifer. These wells can produce a total firm capacity in excess of 7.7 million gallons per day. In 1999, the UCNSB distributed 1.7 billion gallons of water to an estimated 17,505 New Smyrna Beach customers within a 41.3 square mile service area. Seven
wells are located at the Glencoe Road Water Treatment Plant site and six additional wells are located west of this site along S.R. 44. The remaining six wells are located on S.R. 44, 12.5 miles inland. Well depths range from 183 feet to 364 feet, with an average depth of 240 feet (New Smyrna Beach Utilities Commission 1999).

The Floridan Aquifer underlies the entire state of Florida including the Coastal Plain areas of Alabama, Georgia, and South Carolina. In total, the Floridan Aquifer covers an area of about 82,000 square miles (Parker et al. 1955; Parker 1974). Throughout most of the state, the Floridan Aquifer is one large, mostly artesian, hydrogeologic unit. However, in some areas, where confining beds are absent, thin, or discontinuous, water occurs under water table conditions (Parker et al. 1955; Parker 1974).

The Floridan Aquifer is composed of several formations from the Eocene Era. From youngest to oldest, these include: the Suwannee Limestone, the Ocala Limestone, the Avon Park Limestone, and the Lake City Limestone (Toth 1987). The Suwannee Limestone is not found under the Mosquito Lagoon basin and therefore it is the Ocala Limestone that marks the upper limit of the Floridan Aquifer in this region (Woodward-Clyde 1994b). The depth of the top of the Floridan Aquifer varies considerably throughout the state. For example, the top of the Floridan Aquifer under northern Mosquito Lagoon can be found at .23 meters in reference to mean sea level (National Geodetic Vertical Datum: NGVD). In southern Brevard County, the top of the aquifer lies at .61 meters NGVD, and near St. Lucie Inlet the top is found at .229 meters NGVD (Woodward-Clyde 1994b).

In the northern IRL, the intermediate aquifer-confining unit is not very thick, the Floridan Aquifer probably discharges directly to the surficial aquifer naturally due to the upward flow potential from the deeper aquifer during the dry season (Toth 1987). In Volusia County, the confining unit becomes very thin, or even absent in some areas, which allows greater exchange of ground water between the Floridan and the surficial aquifers (Toth 1987). An example of where the Floridan Aquifer discharges to the surface can be found in Turnbull Hammock (Wyrick 1960). Toth (1987) defines the Mosquito Lagoon sub-basin as an area of active
discharge from the Floridan Aquifer. Discharge may occur through springs, artesian wells, or leakage into overlying aquifers through thin or discontinuous confining beds (Provancha et al. 1992). Recharge areas for the Floridan Aquifer in the Mosquito Lagoon region are associated with the karstic Cresent City and DeLand ridges to the north and west of the Lagoon (McGurk et al. 1989). Recharge also occurs, to a lesser degree, as leakage through the surficial sediments in the Eastern Valley and Atlantic Coastal Ridge (Provancha et al. 1992).

The intermediate aquifer is the confining unit between the Floridan and the surficial aquifers. It is composed primarily of the Hawthorn Formation deposited during the Miocene Era (Provancha et al. 1992). This formation is made up of clay and limestone, with some interspersed layers of sand and shell (Woodward-Clyde 1994b). The Hawthorn formation beneath Mosquito Lagoon is relatively thin; it is estimated to be approximately 15 to 30 meters thick (McGurk et al. 1989) and approximately 23 meters below the surface at Ponce de Leon Inlet (Toth 1987). Additionally, at some places in Volusia County, the Hawthorn Formation is absent (Toth 1987). The hydraulic conductivity ranges between only 3.04 x 10-4 and 9.1 x 10-3 meters per day (Provancha et al. 1992).

The surficial aquifer is less extensive than the Floridan Aquifer system and is tapped when the Floridan Aquifer contains non-potable water, as is the case in some areas of the Mosquito Lagoon region, or when the Floridan system is deeper than 61 meters and brackish water occurs (Toth 1987). The surficial aquifer consists of approximately 50 to 100 feet of interbedded sand, shell, and clay sediments including Pleistocene to recent sand, clayey sand, or Anastasia
Formation coquina (Miller 1979, Provancha et al. 1992). Late Miocene and Pliocene sand, shell, and clay layers are also incorporated into the surficial aquifer (McGurk et al. 1989). The top of the surficial aquifer is marked by the water table, and the intermediate confining unit generally marks the bottom. Recharge of this aquifer occurs through infiltration of rainfall and seepage
from lakes, streams, and marshes. Precipitation is the primary source of recharge. Provancha et al. (1992) documented about 0.5% of the average annual rainfall recharging the groundwater reservoir, whereas Erwin (1988) reported about 14% going into groundwater storage.

Dr. Randall Parkinson (formerly of Florida Tech) is presently investigating the surficial geomorphology of MINWR and KSC. Although important for understanding both present biodiversity and water management strategies, to date, these late Quaternary deposits and associated geomorphology (sinkhole lakes, solution creek channels, etc.) have not been mapped. Results from this study are expected in 2001.

Toth, D. 1987. Hydrogeology in Indian River Lagoon Joint Reconnaissance Report. J.S. Steward and J. Van Arman (eds). St. Johns River Water Management District and South Florida Water Management District. Palatka , Florida .

Woodward-Clyde Consultants 1994a. IRLNEP ( Indian River Lagoon National Estuary Project), Physical Features of the Indian River Lagoon. Indian River Lagoon National Estuary Program, Melbourne , FL. Final Technical Report. Project number 92F274C. Tampa , FL.

Woodward-Clyde Consultants 1994b. Status and Trends: Summary of the Indian River Lagoon. Indian River Lagoon National Estuary Program, Melbourne , FL. Final Technical Report. Project number 92F274C. Woodward-Clyde Consultants. Tampa , FL.

Woodward-Clyde Consultants. 1994c. Preliminary Water and Sediment Quality Assessment of ,-, the Indian River Lagoon. Indian River Lagoon National Estuary Program, Melbourne , ' FL. Final Technical Report. Project number 92F274C. Woodward-Clyde Consultants. Tampa , FL.

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